(a) Field of the Invention
The present invention relates to a photographic lens system and, more particularly, to a photographic lens system with a field angle about 45.degree., large aperture ratio of F/2.8, telephoto ratio about 1.0 and short overall length.
(b) Description of the Prior Art
To make the overall length of a wide-angle lens system with four-element lens configuration short, it is known to arrange the lens system as a so-called telephoto type lens system by arranging a concave lens at the rear position in the lens system and to thereby make the telephoto ratio small. The lens system disclosed in Japanese published unexamined patent application No. 38409/82 is known as the above-mentioned type of wide-angle lens system. However, in case of the lens system shown in said patent application, the aperture ratio is small, i.e., F/3.5.